1. Field of the Invention
Computer Program Listing Appendix
A computer program listing appendix on compact disk is included in this application. Appendix A and Appendix B are contained on a compact disk herewith as Appendix A.txt (space included), 51KB, loaded on the disk Nov. 21, 2001, and Appendix B.txt (no space included), 212KB, loaded on the disk Dec. 19, 2001, both of which are in ASCII format for an IBM PC/MS Windows compatible computer system, and both of which are incorporated herein by reference.
This invention relates generally to a display control system and, more particularly without limitation, to a system for controlling the display on the screen of a computer monitor for the purpose of reducing eye strain of, and increasing readability for, a user.
2. Description of the Related Art
Reading has never been a particularly natural task for the human eye, but scanning text on a computer screen appears to be especially more effortful than it is on a printed page. While the popular view of this phenomenon is that text on computers causes eye strain, it is more likely that text viewing generally increases the cognitive load on the user in a variety of ways. One of the main factors that may contribute to difficulty reading text on a computer screen has to do with document length. A common solution used to display long documents is to scroll the screen to bring more of the material into view. Prior art employs two scrolling strategies: screen-by-screen, line-by-line. The problem is that, however efficient these scrolling strategies are from an engineering standpoint, they may actually make the reading task more difficult for the user. The relevant issues encompass three key aspects of readability, namely reading speed, reading comprehension, and reading ease, each of which can be observed and measured as viewer performance variables. Content complexity can be considered a control variable, and should be used to distinguish effects among the three performance variables bearing on readability.
Users employ two strategies to move down through a long document, either to advance screen-by-screen or line-by-line, neither one of which is conducive to natural reading. Scrolling screen-by-screen is disruptive to the reading experience because it causes users to lose their place, forcing them to free cognitive resources away from text comprehension in order to reorient the eye in the proper location in the text. The other option is to scroll line-by-line, ensuring that only previously viewed material is removed from view, not new material. However, this imposes a control task on the reader that similarly drains cognitive resources away from the primary task of text comprehension.
Such strain is due in part to the sudden and repetitive vertical shifting of screen contents and the natural attempt by the human visual system to follow such apparent motions. It may also be due in part to a reduction of blinking, since the flicker caused by scrolling spoofs physical blinking. Continuous scrolling, by more or less constant vertical motion of screen contents, likewise subjects the viewer to strain due to finer, but more frequent, vertical steps and flicker. Furthermore, continuous scrolling rarely achieves real freedom from the distraction of display control; reading speed normally varies with content complexity, which may change substantially both within and between documents.
Thus, in choosing any of the commonly available scrolling strategies for consuming substantial reading material on-screen, the readability of the material is normally compromised. This happens either by disruptions in information flow, by distractions from the task of consuming and comprehending information, or by additional eye stress and fatigue. Fatigue may even foreshorten the consumption of significant amounts of readable material and affect comprehension.
Another problem with using a computer monitor for consuming readable material is that lines of text generally span from near one side of the monitor to the other. This may require substantial lateral eye movement for every line of text, which can cause user fatigue. Upon completion of reading one line of test, the human visual system generally retraces the line to find the beginning of the subsequent line of text. If the line of text is too long relative to its height, retrace errors can occur, disrupting the flow of information similarly to the incomplete scrolling problem previously described. Thus, readability is again compromised in reading ease and reading speed domains.
Prior art attempts to resolve this particular problem generally introduces either reduced-width columns or multiple columns of material on-screen. Reduced-width columns are certainly more readable, having shorter lines that are more easily retraced. However, reduced width columns also result in more scrolling, since the area required to present the material is more or less fixed, and reducing the width merely increases the depth needed to be reached by scrolling. Multiple columns of material may also result in reduced column width. However, the typical presentation layout principle is to form columns with a sufficient depth to reach the bottom of the printable page, and is primarily suited for off-screen consumption. Alternatively, a presentation layout principle for on-screen consumption is to more or less balance the depth of the columns. In this case, the scrolling task is even greater; the viewer must scroll to the bottom of a column and then scroll completely back to the top of the subsequent column. Thus, these prior art attempts to manage column widths may actually result in additional losses to readability.
Another common problem is the use of inappropriate type fonts in presenting material on-screen. The publisher may make use of rather small fonts, which can crowd more information onto the screen at once, thereby reducing the amount of scrolling required for complete consumption of the presented information. This strategy generally results in additional eye strain, due to squinting or straining to read uncomfortably small print, and due to increased retrace errors caused by long narrow lines of text. Again, readability is compromised. The significance of type fonts as bearing on readability is dependent on individual viewers (visual acuity) and on their environment (external lighting and monitor quality). Individual response to eye strain, as caused by small fonts or repetitive vertical scrolling, may invoke symptoms of optokinetic nystagmus, which is an involuntary eye reflex further enhanced by eye strain, which may also negatively affect reading performance. Nystagmus may arise regardless of font selection, however, due to eye strain induced by scrolling alone. The viewing environment issues (external lighting and monitor quality) may be considered noise factors in measuring readability, requiring controlled experimentation and statistical analysis. The intent of the publisher of the document is, presumably, to present information appropriately by predetermined font selections. Due to individual viewer preferences and environment factors, such intentions may well result in a higher rate of eye strain and reduced readability than normally considered or assumed.
Prior art often permits the viewer to adjust the size(s) of the type font used to render the document on-screen. The effort to discover and use methods to modify font size may discourage their use. More significantly, the presentation layout principles incorporated in the prior art are often inadequate to desirably fulfill viewer requirements to improve readability through font size modification. As an example, consider the implementation of multiple columns for a recent release of a web browser: the number of columns is prescribed by the web page author and cannot be modified by the viewer. As the viewer overrides the publisher""s font selections in order to significantly enlarge font sizes for his own particular situation, the quality of the layout can be compromised. For instance, lines of text can easily contain too few characters, with large gaps for words that might preferably be hyphenated. In addition, there is a disproportionate increase in the rate of retracing and the amount of requisite scrolling. All this results in a substantial reduction in readability.
Similarly, when a person engages in reading a lengthy publication, a natural tendency is to settle back in the chair for comfort. When reading printed material, this is generally a well-supported activity; unless the publication itself is too heavy, the reading distance is easily maintained. For on-screen consumption of information, however, reading distance is not easily maintained even with laptop computers. Viewers could clearly benefit by simply increasing font sizes in proportion to the increased reading distances afforded by more comfortable sitting positions. However, the practical difficulties in accomplishing this simple goal with prior art are quite apparently rather significant. Font size modifications by the viewer, in and of themselves, are generally inadequate to enhance readability using the prior art.
Thus, what is needed is a system for enhancing the readability of on-screen presentations of information. Such a system would eliminate the need for scrolling. It would also limit the line widths of readable text to a useful range. It would also allow the viewer to easily modify font size and apply better presentation layout principles to preserve and enhance on-screen consumption of information.
An improved system is provided for on-screen publishing of documents, including combinations of text, graphics, and tables, to the consumer. The key features of this system include: precluding the use of window scrolling, to accommodate information too extensive to be displayed at one time, through the use of page-turning techniques; conforming this information to multiple columns to enhance readability; and integrating, in the multiple column layout on the on-screen presentation, font resizing operations conducted by the information consumer.
More specifically, an improved computer system is provided for automatically converting a scrollable electronic document, including text, graphics, tables and combinations thereof, from a scrollable format to a non-scrollable format, the system comprising a page-forming mechanism configured to operatively and automatically arrange the scrollable electronic information document into a plurality of non-scrollable pages, each having one or more columns wherein each of the columns has a width corresponding to a number of characters per line within a predetermined range of characters per line; a screen having a display window configured to simultaneously display a selected one of the plurality of non-scrollable pages in its entirety; and a page-turning mechanism configured to selectively, sequentially and individually display the plurality of non-scrollable pages in the display window. The page-forming mechanism may include a content formatter mechanism that is configured to be operatively responsive to formatting commands, either common word-processing commands or html commands or both, embedded in the electronic document. The page-forming mechanism includes a font-sizing mechanism configured to operatively permit a user to selectively alter the size of the characters comprising the non-scrollable pages. Also, the system includes an image sizing mechanism configured either to automatically alter the widths of graphic images and tables in the electronic document to proportionately conform to the width of the one or more columns, or to reduce the graphic images and tables to selectively expandable icons positioned in the displayed document.
Briefly, a first described embodiment of the present invention is configured to manipulate text utilizing common word-processing commands and graphics images embedded in a source document, whereas a modified embodiment thereof is configured to additionally manipulate tables and utilize html commands embedded in the source document.
A method is provided for practicing the invention.
The principal objects and advantages of the present invention include: providing a system and method for eliminating scrolling while viewing lengthy material on a monitor; providing such a system and method that establishes a maximum line width for text intended to be read by a user; providing such a system and method for permitting a user to selectively enlarge information printed in small fonts such that the material can be easily read while the user sits at a comfortable viewing distance from the monitor; providing such a system and method for automatically recalculating the number of displayed columns in response to a user change in size of displayed font; providing such a system and method for automatically reformatting displayed material in response to a user change in size of displayed font; providing such a system and method for automatically resizing graphics images embedded in a source document to fit within a column; providing such a system and method for automatically converting graphics images embedded in a source document to an icon or object image that is selectively expandable and reconvertable to the originally intended image; providing such a system and method for automatically resizing tables embedded in a source document to fit within a column; providing such a system and method for automatically converting tables embedded in a source document to an icon or object image that is selectively expandable and reconvertable to the originally intended table display; and is generally providing such a system and method that is efficient in operation, reliable in performance, capable of long operating life, and is particularly well adapted for the proposed usage thereof.
Other objects and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, which constitute a part of this specification and wherein are set forth exemplary embodiments of the present invention to illustrate various objects and features thereof.